1. Field of the Invention
The present invention relates to a multi-band antenna, and more particularly to a built-in multi-band antenna capable of being assembled in a portable mobile communication device.
2. The Related Art
In recent years, with the rapid development of mobile communication technology, portable mobile communication devices, such as cell phones and notebooks, need be developed faster and faster to meet overgrowing requirements of people. It's a trend for the portable mobile communication device to operate in multiple wireless wide area network systems covering different frequency ranges so as to keep a good communication performance anywhere. Accordingly, a multi-band antenna is needed to be assembled in the portable mobile communication device. However, the built-in multi-band antenna which is common-used, such as a planar inverted-F antenna (PIFA), has a complex structure, a larger volume and a higher manufacture cost. Consequently, utilization ratio of the common-used multi-band antenna is lower due to limitations of the complex structure, the larger volume and the higher manufacture cost of the multi-band antenna.
In consideration of the portable mobile communication device being developed towards a miniaturized direction, an innovative built-in multi-band antenna should be designed to have a simplified structure and a smaller volume in order to be conveniently assembled in the portable mobile communication device for remedying the defects of the common-used multi-band antenna and lower a manufacture cost of the multi-band antenna.